The concepts of asthma endotypes and phenotypes to guide current and novel treatment strategies.

INTRODUCTION: Asthma, a common, non-communicable chronic disease affects over 300 million individuals worldwide. The Western world lifestyle is claimed to be responsible for this high and increasing prevalence. Asthma has been defined as a syndrome with various phenotypes and endotypes, allergic asthma and type 2 asthma being the most frequent. A great increase in prevalence of allergic diseases has necessitated intensive investigations both for understanding the underlying mechanisms and for the development of novel therapy options with long-term efficacy and limited side-effects. Allergic patients demonstrate unique presentations with variable visible characteristics and disease outcomes depending on different molecular mechanisms, related to influence of genes and epigenetic control by micro- and macro-environment. Areas covered: This article reviews the definition of asthma phenotypes and possible endotypes, advances in allergy-immunology field and contemporary personalized therapy options for asthma. Expert commentary: Better understanding of the complex immune network of allergic inflammation and key players of immunity is continuously being provided for clarification of asthma sub-types. Successful therapy of asthma requires better definition of underlying pathogenesis, which sequentially could end up with 'custom-tailored' individualized, evidence-based and more precise therapy options; a new era termed as 'precision medicine'. Endotype, phenotype, theratype and biomarker terms arise as major keywords in precision/personalized medicine.